Blade dovetail and retention apparatus

Abstract

Methods, apparatus, systems, and articles of manufacture are disclosed to adjust a pitch axis of a blade of an engine. An example blade apparatus includes: a hub to facilitate movement of blades in an engine, the engine having a radial center line; and a trunnion connected to the hub. The example trunnion includes a slot to accommodate a first blade, and at least one of the trunnion or the first blade is positioned with at least one of a tilt or a lean with respect to the radial center line to form a pitch axis offset from the radial center line such that the pitch axis is not parallel to or co-linear with the radial center line. The example hub is to rotate the first blade about the pitch axis.

What is claimed is: 
     
       1. A blade apparatus comprising:
 a hub to facilitate movement of blades in an engine, the engine having a radial center line; and 
 a trunnion connected to the hub, the trunnion including a slot to accommodate a first blade, at least one of the trunnion or the first blade positioned with a combination of a forward tilt forward of a direction of rotation and a tangential lean in the direction of rotation and with respect to the radial center line to form a pitch axis offset from the radial center line such that the pitch axis is not parallel to or co-linear with the radial center line, the hub to rotate the first blade about the pitch axis, 
 wherein at least one of the hub or the trunnion is machined to generate the forward tilt and the tangential lean, the combination of the forward tilt and the tangential lean determined to set the pitch axis according to a moment reaction at the trunnion. 
 
     
     
       2. The blade apparatus of  claim 1 , further including at least one bearing, the at least one bearing mounted to the hub and at least one of connected to or integrated with the trunnion. 
     
     
       3. The blade apparatus of  claim 1 , wherein the tangential lean is into or away from a direction of rotation. 
     
     
       4. The blade apparatus of  claim 1 , wherein a position of the first blade is modeled to simulate and resolve reactions based on a point of attachment between the first blade and the trunnion. 
     
     
       5. The blade apparatus of  claim 4 , wherein at least one of the point of attachment or an orientation of the first blade are determined based on the simulated reactions on the first blade. 
     
     
       6. The blade apparatus of  claim 1 , further including a ram positioned with respect to the first blade in the trunnion. 
     
     
       7. The blade apparatus of  claim 1 , further including at least one of a spring or a wedge positioned with respect to the first blade in the trunnion. 
     
     
       8. A rotor apparatus comprising:
 movement means to facilitate movement of blades in an engine, the engine having a radial center line; and 
 connection means to accommodate a first blade, at least one of the connection means or the first blade positioned with a combination of a forward tilt forward of a direction of rotation and a tangential lean in the direction of rotation and with respect to the radial center line to form a pitch axis offset from the radial center line such that the pitch axis is not parallel to or co-linear with the radial center line, the movement means to rotate the first blade about the pitch axis, 
 wherein at least one of the movement means or the connection means is machined to generate the forward tilt and the tangential lean, the combination of the forward tilt and the tangential lean determined to set the pitch axis according to a moment reaction at the connection means. 
 
     
     
       9. The rotor apparatus of  claim 8 , further including a retention means to retain the blade in the connection means. 
     
     
       10. A computer-implemented method to determine blade position to set a pitch axis relative to a radial engine axis, the method comprising:
 adjusting a position of a model of a blade at a location with respect to a trunnion attached to a hub of an engine; 
 applying loads to the model; 
 solving the model to resolve reactions caused by the loads; 
 predicting one or more outputs based on the model solution; 
 determining a combination of a forward tilt forward of a direction of rotation and a tangential lean of the blade in the direction of rotation based on the one or more outputs; and 
 generating a blade position to form a pitch axis offset from a radial center line of the engine such that the pitch axis is not parallel to or co-linear with the radial center line, the blade to rotate about the pitch axis, the combination of the forward tilt and the tangential lean determined to set the pitch axis according to a moment reaction at the trunnion. 
 
     
     
       11. The method of  claim 10 , wherein the one or more outputs include a plurality of outputs, and further including combining the outputs to create a weighted output parameter. 
     
     
       12. The method of  claim 10 , further including evaluating an outcome of the blade position. 
     
     
       13. The method of  claim 10 , wherein the model is a finite element model and wherein the position of the blade is modeled to simulate and resolve reactions based on a point of attachment between the blade and the trunnion. 
     
     
       14. The method of  claim 13 , wherein at least one of the point of attachment or an orientation of the blade are determined based on the reactions simulated and resolved on the blade. 
     
     
       15. The method of  claim 10 , wherein the location is a first location, and further including modifying the location to a second location and repeating the method. 
     
     
       16. The method of  claim 10 , further including creating a design space to at least one of lean or tilt the pitch axis within a range. 
     
     
       17. The blade apparatus of  claim 1 , wherein the combination of the forward tilt and the tangential lean is determined based on a modeled moment reaction.